Ozonolysis process and intermediates in the manufacture of 17-oxygenated 2-oxa-5alpha-androstan-3-ones



United States Patent ,0

The present invention relates to a novel process in the manufacture of 17-owgenated 2-oxa-5a-androstan-3-ones and to the novel intermediates formed by that process. Those 2-oxa compounds are represented by the formula wherein R is hydrogen or a lower alkyl radical and R is hydrogen or a methyl radical. They are potent anabolic agents, as is disclosed in the copending application of Raphael Pappo, Serial No. 158,577, filed December 11, 1961.

The aforementioned intermediates are represented by the formula CH3 I/\ wherein R is hydrogen or a methyl radical, X is a carbonyl, B-hydro-xymethylene, fi-(lower alkanoyDoxymethylenc, a-(lower alkyl)-,8hydroxymethylene, or a-(lower alkyD-fi-(lower alkanoyDoxymethylene radical, and A is a methyl or forrnyl group.

The term lower alkyl encompasses, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, and the branchedchain radicals isomeric therewith.

Starting materials suitable for utilization in the instant process are represented by the formula CHa y 1'1 l I wherein R and X have the identical meanings indicated above. Reaction of these substances With ozone produces the above-described intermediates. This process is preferably conducted at a temperature of 70 to 30 in an organic solvent-medium consisting of a non-polar solvent and optionally including a polar solvent also. Typical non-polar solvents are methylene chloride, chloroform, carbon tetrachloride, and ethyl acetate, while the polar solvent is exemplified by the family of lower alkanols, i.e. methanol, ethanol, tertiary-butyl alcohol, etc. Preferably, a slight excess of ozone is used, the presence of excess reagent being detected by its characteristic blue color. Some advantages of the instant process over previously disclosed methods are the utilization of inexpensive reagents and relatively short reaction times, and the production of high yields.

When a polar solvent, for example methanol, is included in the process, intermediates of the formula These processes are specifically illustrated by the reaction of 1713 hydroxy 170. methyl-5 cz-Zti'ldIOSll-l-tBH-3-OI1G in methylene chloride and methanol with ozone to produce methyl 17/3-hydroxy -170z methyl-l-oxo-1,2-seco-A-nor- Soc-ZIIlClIOSlIZtl'l-Z-OQIB and, alternatively, with ozone in methylene chloride to yield 17/3-l1ydroxy-l7a-methyl-loxo-l,Z-seco-A-nor-Sa-androstan-2-oic formic anhydiide.

The aforementioned 1,2-seco intermediates are converted to the corresponding anabolic 2-oxa compounds by treatment with a reducing agent in aqueous medium. Typically, the aforementioned methyl 17fl-hY-(lI'OXY-17Ctmethyl-l-oxo-1,Z-seco-A-nOr-Sa-androstan-2-oate is contacted with sodium borohydride in aqueous sodium hydroxide, resulting in .17,Bhydroxy-l7a-methyl-2-oxa-5aandrostan-S-one. a

The invention will appear more fully from the examples which follow. These examples are given by way of illustration only and are not to be construed as limiting the invention either in spirit orin scope. Temperatures are given in degrees Centigrade C.),.and quantities of materials in parts by weight unless otherwise noted.

Example 1 Into a solution of 10 parts of l7e-hydroxy-l7wmethyl- 5a-androst-1-en-3-one in 800 parts of carbon tetrachloride is bubbled, at -20, a stream of oxygen containing 68% of ozone. The gas addition is continued until the presence of excess ozone is indicated by its characteristic blue color. A stream of nitrogen is passed through the mixture to purge it of the excess oxidant. The solid which separates is collected by filtration, dissolved in methylene chloride, and this solution is allowed to stand on CH3 on.

HCOC

Example 2 A solution of 15 parts of l7,8-hydroxy-17m-methyl-5aandrst-1-en-3-0ne in 200 parts of methylene chloride containing 240 parts of methanol is treated with ozone according to the procedure of Example 1. The reaction mixture, after it has been purged with nitrogen, is contrated to dryness and the resulting residue is recrystallized from aqueous methanol to yield crude methyl 1713- hydroxy 17cc methyl-1-oxo-1,2-seco-A-nor-5ot-androstan-Z-oate, M.P. about 125-140. Further purification is effected by adsorption of a benzene-hexane solution of this substance on silica gel followed by elution With 20% ethyl acetate in benzene to aiford a pure sample melting at about 144-145". It is represented by the formula -om o i II no CHsOC ll\/Iii Example 3 An aqueous slurry of 6 parts of methyl 17p+hydroxy- 17a methyl-1-oxo-1,2-seco-A-nor-5a-androstan-2-oate in 100 parts of water containing 100 parts of methanol is made alkaline to pH 10 by the addition of dilute aqueous sodium hydroxide, then is treated with 6 parts of sodium borohydride. This mixture is allowed to react at room temperature for about 16 hours. Benzene is added, and the resulting mixture is acidified carefully with dilute "hydrochloric acid. The benzene layer is then separated, and the aqueous layer is further extracted with benzene. The combined benzene extracts are washed successively with aqueous potassium bicarbonate and water, dried over anhydrous sodium sulfate, then evaporated to dryness in vacuo. The resulting residue is triturated with ether to aiford pure 17fl-hydroxy-l7a-methyl-2-oxa-5aandrostan-B-one, M.P. about 235-238; [a] =--Z3 (chloroform) Example 4 The substitution of 6 parts of 17B-hydroxy-17a-methyl- 1-oxo-1,2-seco-A nor 5a-androstan-2-oic formic anhycording to the process of Example 3, affords 17[3-hydroxy-2-oxa-5a-androstan-3-one, M.P. about 198-2032 Example 6 The substitution of an equivalent quantity of 17aethyl-17fl-hydroxy-5a-androst-1-en-3-one in the procedure of Example 1, followed by reaction of the resulting product with sodium borohydride by the process of Example 3, alfords 17cx-ethyl-17,6-hydroxy-2-oxa-5u-androstan-3-one, M.P. about 192-195 Example 7 By substituting an equivalent quantity of -acetoxy- 5u-androst-1-en-3-one and otherwise proceeding according to the processes of Example 1, a product is obtained,

which product is converted by the procedure of Example 3 to 1713-l'1YdIOXY-Z-OXfi-Sa-findlOStfln3-OI1, M.P. about 198-203", identical with the product of Example 5.

Example 8 CH3 C H:

/X l l wherein X is selected from the group of radicals consisting of carbonyl, B-hydroxymethylene, and O2-(1OWIa1- kyl)-18-hydroxymethylene, with ozone.

4. A process which comprises contacting a compound of the formula OH --(l0wer alkyl) with ozone.

5. A process which comprises contacting 17oc-methyl-5a-androst-1-en-3-one with ozone.

6. A process which comprises contacting droxy-5u-androst-1-en 3-one with ozone.

7. A process which comprises contacting Sax-androst- 1-ene-3,17-dione with ozone.

References Cited in the tile of this patent UNITED STATES PATENTS 2,897,202 Wildi July 28, 1959 3,023,227 Atwater Feb. 27, 1962 OTHER REFERENCES Hufiman: Iour. Amer. Chem. Soc., volume 70 (1948) page 4268.

17p-hydroxyl'ip-hy- I 

1. METHYL 17B-HYDROXY-17A-METHYL-1-OXO-1,2-SECO-ANOR-5A-ANDROSTAN-2-OATE.
 3. A PROCESS WHICH COMPRISES CONTACTING A COMPOUND OF THE FORMULA 